1. Field of the Invention
The present invention relates to a slide fastener stringer having a woven stringer tape and a filamentary coupling element woven into the tape along a longitudinal edge thereof.
2. Prior Art
Slide fastener stringers including a woven coupling element are generally made on shuttleless looms or ribbon looms with a shuttle, the element being in the shape of a coil or zigzag formed from a monofilament. The monofilament is supplied warpwise or weftwise as it is shaped and woven into the tape while the tape is being produced. The monofilament has a plurality of widened, flattened portions formed as by stamping and disposed at spaced intervals therealong. The monofilament is bent or curved at such portions, and every other such portions acting as coupling heads of the element are bent around a mandrel arranged along the stringer tape, the remaining portions being curved around a core thread extending warpwise for being disposed in and along the coupling element. According to another prior process, no core thread is used and the monofilament is shaped into a meandering type element by being beaten up by a reed (Japanese Utility Model Laid-Open Publication No. 50-155339).
Difficulties common to such conventional slide fastener stringers are that the monofilament tends to be bent or curved irregularly and, when such irregularities build up, a resulting element becomes distorted in shape. Further, since the element is supported on the tape less securely and hence is positionally unstable, slide fasteners with such element cannot be used on articles that are expected to meet severe pulls.